UCSF Medical Center, the city’s health care giant, will grow by more than 30 percent by 2035, adding new hospitals, research labs, medical offices and housing at sites across the city.

The university’s long-range development plan also calls for razing and replacing aging Moffitt Hospital on its flagship Parnassus Heights campus and demolition of three structures at Mt. Zion Medical Center, including the 1914 Hellman Building, the site’s original hospital. The university also intends to sell or lease its Laurel Heights site, most likely for a housing development.

The development plan, which was recently presented to the city’s Planning Commission, is more of a guide than a blueprint, with changes in direction likely over the next 20-plus years, Lori Yamauchi, assistant vice chancellor for campus planning, said in an interview.

“We don’t really know what we will need in the future, because we tend to be opportunistic in our growth,” with research grants, donor interests and other concerns playing a role in those decisions, she added.

Drivers of the anticipated expansion include a boost in research funding, outpatient volume that has soared by 93 percent since 1997, efforts to meet upcoming tougher seismic standards for hospitals and a desire to consolidate the university’s far-flung resources, which are now spread across 19 separate sites in San Francisco.